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Google ACE Practice Question: A developer reports that a Cloud Function is…
A developer reports that a Cloud Function is failing with '403 Forbidden' when calling the BigQuery API. The function's service account has the BigQuery Data Viewer role. What is a likely additional requirement that may be missing?
⚠ Common exam trap
Google Cloud often tests the distinction between IAM permissions and API enablement, trapping candidates who assume a 403 always means a missing IAM role rather than a disabled API.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The BigQuery API may not be enabled in the Cloud Functions' project
The 403 Forbidden error indicates that the Cloud Function's service account lacks the necessary permissions to call the BigQuery API. Even with the correct IAM role (BigQuery Data Viewer), the BigQuery API must be explicitly enabled in the project where the Cloud Function is running, as Google Cloud requires APIs to be activated per project before they can be used. Without enabling the API, any API call from the function will be rejected with a 403, regardless of IAM roles.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The Cloud Function must be deployed in the same region as the BigQuery dataset
Why it's wrong here
BigQuery is a global service with a single API endpoint, and dataset location is a metadata property, not a connection requirement. A Cloud Function deployed in us-central1 can query a dataset stored in europe-west4 without any special configuration beyond enabling the API. Data residency affects processing location but does not require the function and dataset to share the same region; therefore, region mismatch is never the cause of a failed API call.
- ✓
The BigQuery API may not be enabled in the Cloud Functions' project
Why this is correct
Google Cloud requires the BigQuery API (bigquery.googleapis.com) to be explicitly enabled on the project where the Cloud Function runs. Even if the function's service account has BigQuery Data Viewer or Admin permissions, calls to bigquery.googleapis.com will fail with an error such as 'API has not been used in project X before or it is disabled' when the API is off. Enabling the API in the Cloud Functions project is a prerequisite that developers often overlook when debugging 'permission denied' messages.
- ✗
Cloud Functions cannot call BigQuery — it must use Dataflow or BigQuery scheduled queries instead
Why it's wrong here
Cloud Functions fully supports calling the BigQuery API through official client libraries such as google-cloud-bigquery for Node.js or Python, so no intermediate service is required. Dataflow and scheduled queries are appropriate for batch or streaming pipelines, not for simple API invocations triggered by HTTP or Cloud Storage events. The statement is factually incorrect, as Cloud Functions and BigQuery are commonly integrated in lightweight event-driven workflows.
- ✗
The service account needs the BigQuery Admin role instead of Data Viewer to make API calls
Why it's wrong here
Granting the BigQuery Admin role would not fix the root cause because an API-disabled error occurs before IAM policy evaluation. BigQuery Data Viewer already includes the read permissions (e.g., bigquery.tables.getData) needed for simple data access, and the failure persists regardless of role scope. The real problem is almost always the target API not being enabled.
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Google Cloud Platform Overview
Key term
Google Cloud
Google Cloud is a suite of cloud computing services offered by Google that provides infrastructure, platform, and software solutions over the internet.
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ACE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ACE exam.